FILM REVIEW; Courtesy and Decency Play Sneaky With a Tough Guy

Hank Grotowski (Billy Bob Thornton) is, like his father and his son, a Georgia corrections officer. Leticia Musgrove (Halle Berry) is a waitress struggling to make ends meet and to raise her 12-year-old son. She is also the widow of a man whose execution Hank helped to conduct. The relationship between Hank and Leticia, a relationship born of chance, moral reflex and desperate need, is at the center of ''Monster's Ball,'' a tough, heartfelt new film from the young Swiss-born director Marc Forster.

In outline, the story of Hank and Leticia's entwined lives might seem implausible, and the events that surround it -- three deaths, including the unblinkingly filmed electrocution of Leticia's husband, Lawrence (Sean Combs) -- could have smothered the movie in melodrama. ''Monster's Ball'' could easily have been an exercise in liberal high-mindedness, a cinematic lecture on the inhumanity of the death penalty or the legacy of Southern racism. But Mr. Forster and the screenwriters, Milo Addica and Will Rokos (who is a native of Georgia), are more interested in the details of character and milieu than in deducing right-thinking morals.

Hank and Leticia are not easy people, and much to its credit, ''Monster's Ball'' is not an easy picture. Mr. Forster's deliberate pacing and the gritty, smudged look that Roberto Schaefer, the cinematographer, brings to the workaday modern South create an atmosphere heavy with the buried emotions of grief, rage and terror. Hank lives in the shadow of his bullying, bigoted father (Peter Boyle) and a brutal code of masculine behavior that blocks all access to feeling. But if Hank feels at all sorry for himself, he does not show us, and Mr. Thornton earns our sympathy the hard way, by showing us Hank at his unvarnished worst. ''You've always hated me, haven't you,'' demands his son, Sonny (Heath Ledger), a sensitive, troubled soul who is clearly not cut out for death row duty. ''Yes, I have,'' is Hank's even-toned reply.

The night before, Sonny had incurred his father's wrath by showing intolerable weakness during Musgrove's walk to the electric chair. As one of his African-American colleagues tried to pull him off his son, Hank exploded in an obscene, racist tirade. ''This is not you, Hank,'' his co-worker insisted, trying to calm him down. ''This is me,'' Hank yells back. ''This is me.''

He's right. Hank's prejudice and suspicion are not simply mistaken attitudes in need of correction; they are integral to his character. But so is a habitual courtesy -- the writers catch the quiet politeness that inflects even the most tense or hostile exchanges -- and a reluctant sense of decency. These qualities overtake the others in a way that surprises Hank himself, and his transformation -- in Hollywood, as in the Baptist church, they like to call it redemption -- is all the more astonishing for being almost surreptitious.

Mr. Thornton, one of the most gifted screen actors working today, outdoes himself. For her part, Ms. Berry proves herself to be an actress of impressive courage and insight. Like Hank, Leticia is a character who could have been simplified, turned into a one-dimensional victim or a saint. Ms. Berry emphasizes the character's temper, and also the vulnerability beneath her toughness.

What she has in common with Hank is an alienation from her finer emotions. She loves her son, Tyrell (well played by 10-year-old Coronji Calhoun in his first film role), but he is also the target of her anger and shame. In the last minutes of the movie, the burden of dramatic resolution falls squarely on Ms. Berry, and she soars. The film's conclusion is an enormous gamble for the filmmakers, as well as for Leticia and Hank, and it is above all Ms. Berry's fearless concentration that converts potential sentimentality into honest, complex emotion.

The characters and the bond that develops between them are too complex for words, and the writers use very few. Their economy and the eloquence of Mr. Forster's unshowily beautiful images give ''Monster's Ball'' the density and strangeness of real life. The raw intimacy of some of the scenes -- whether they take place at a diner, in the death house or in the bedroom -- is breathtaking. In the end, the movie belongs to the actors -- to Ms. Berry and Mr. Thornton, principally, but also to the large supporting cast, including Mr. Combs, Mr. Ledger and the hip-hop star Mos Def (as Hank's neighbor down the road). This is one of those rare movies in which even people glimpsed only for a moment or two seem to have lives that ramify beyond the screen, as if the story were being witnessed rather than dramatized.

Directed by Marc Forster; written by Milo Addica and Will Rokos; director of photography, Roberto Schaefer; edited by Matt Chesse; production designer, Monroe Kelly; produced by Lee Daniels; released by Lions Gate Films. Running time: 108 minutes. This film is rated R.